Make rustc pulls on CI more frequent

.github/workflows/rustc-pull.yml

@@ -3,8 +3,8 @@ name: rustc-pull
 on:
   workflow_dispatch:
   schedule:
-    # Run at 04:00 UTC every Monday
-    - cron: '0 4 * * 1'
+    # Run at 04:00 UTC every day
+    - cron: '0 4 * * *'
 
 jobs:
   pull:
@@ -34,15 +34,33 @@ jobs:
           git config --global user.name 'The rustc-dev-guide Cronjob Bot'
           git config --global user.email '[email protected]'
       - name: Perform rustc-pull
-        run: cargo run --manifest-path josh-sync/Cargo.toml -- rustc-pull
+        id: rustc-pull
+        # Turn off -e to disable early exit
+        shell: bash {0}
+        run: |
+          cargo run --manifest-path josh-sync/Cargo.toml -- rustc-pull
+          exitcode=$?
+
+          # If no pull was performed, we want to mark this job as successful,
+          # but we do not want to perform the follow-up steps.
+          if [ $exitcode -eq 0 ]; then
+            echo "pull_result=pull-finished" >> $GITHUB_OUTPUT
+          elif [ $exitcode -eq 2 ]; then
+            echo "pull_result=skipped" >> $GITHUB_OUTPUT
+            exitcode=0
+          fi
+
+          exit ${exitcode}
       - name: Push changes to a branch
+        if: ${{ steps.rustc-pull.outputs.pull_result == 'pull-finished' }}
         run: |
           # Update a sticky branch that is used only for rustc pulls
           BRANCH="rustc-pull"
           git switch -c $BRANCH
           git push -u origin $BRANCH --force
       - name: Create pull request
         id: update-pr
+        if: ${{ steps.rustc-pull.outputs.pull_result == 'pull-finished' }}
         run: |
           # Check if an open pull request for an rustc pull update already exists
           # If it does, the previous push has just updated it
@@ -54,6 +72,7 @@ jobs:
             echo "pr_url=$PR_URL" >> $GITHUB_OUTPUT
           else
             PR_URL=`gh pr list --author github-actions[bot] --state open -q 'map(select(.title=="Rustc pull update")) | .[0].url' --json url,title`
+            echo "Updating pull request ${PR_URL}"
             echo "pr_url=$PR_URL" >> $GITHUB_OUTPUT
           fi
         env:
@@ -64,16 +83,23 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Compute message
-        id: message
+        id: create-message
         run: |
-          if [ "${{ needs.pull.result }}" == "failure" ];
-          then
+          if [ "${{ needs.pull.result }}" == "failure" ]; then
             WORKFLOW_URL="${{ github.server_url }}/${{ github.repository }}/actions/runs/${{ github.run_id }}"
             echo "message=Rustc pull sync failed. Check out the [workflow URL]($WORKFLOW_URL)." >> $GITHUB_OUTPUT
           else
-            echo "message=Rustc pull sync succeeded. Check out the [PR](${{ needs.pull.outputs.pr_url }})." >> $GITHUB_OUTPUT
+            CREATED_AT=`gh pr list --author github-actions[bot] --state open -q 'map(select(.title=="Rustc pull update")) | .[0].createdAt' --json createdAt,title`
+            PR_URL=`gh pr list --author github-actions[bot] --state open -q 'map(select(.title=="Rustc pull update")) | .[0].url' --json url,title`
+            week_ago=$(date +%F -d '7 days ago')
+
+            # If there is an open PR that is at least a week old, post a message about it
+            if [[ -n $DATE_GH && $DATE_GH < $week_ago ]]; then
+              echo "message=A PR with a Rustc pull has been opened for more a week. Check out the [PR](${PR_URL})." >> $GITHUB_OUTPUT
+            fi
           fi
       - name: Send a Zulip message about updated PR
+        if: ${{ steps.create-message.outputs.message != '' }}
         uses: zulip/github-actions-zulip/send-message@e4c8f27c732ba9bd98ac6be0583096dea82feea5
         with:
           api-key: ${{ secrets.ZULIP_API_TOKEN }}

josh-sync/src/main.rs

@@ -1,5 +1,5 @@
 use clap::Parser;
-use crate::sync::GitSync;
+use crate::sync::{GitSync, RustcPullError};
 
 mod sync;
 
@@ -22,7 +22,18 @@ fn main() -> anyhow::Result<()> {
     let sync = GitSync::from_current_dir()?;
     match args {
         Args::RustcPull => {
-            sync.rustc_pull(None)?;
+            if let Err(error) = sync.rustc_pull(None) {
+                match error {
+                    RustcPullError::NothingToPull => {
+                        eprintln!("Nothing to pull");
+                        std::process::exit(2);
+                    }
+                    RustcPullError::PullFailed(error) => {
+                        eprintln!("Pull failure: {error:?}");
+                        std::process::exit(1);
+                    }
+                }
+            }
         }
         Args::RustcPush { github_username, branch } => {
             sync.rustc_push(github_username, branch)?;

josh-sync/src/sync.rs

@@ -11,6 +11,19 @@ const JOSH_FILTER: &str = ":/src/doc/rustc-dev-guide";
 const JOSH_PORT: u16 = 42042;
 const UPSTREAM_REPO: &str = "rust-lang/rust";
 
+pub enum RustcPullError {
+    /// No changes are available to be pulled.
+    NothingToPull,
+    /// A rustc-pull has failed, probably a git operation error has occurred.
+    PullFailed(anyhow::Error)
+}
+
+impl<E> From<E> for RustcPullError where E: Into<anyhow::Error> {
+    fn from(error: E) -> Self {
+        Self::PullFailed(error.into())
+    }
+}
+
 pub struct GitSync {
     dir: PathBuf,
 }
@@ -24,7 +37,7 @@ impl GitSync {
         })
     }
 
-    pub fn rustc_pull(&self, commit: Option<String>) -> anyhow::Result<()> {
+    pub fn rustc_pull(&self, commit: Option<String>) -> Result<(), RustcPullError> {
         let sh = Shell::new()?;
         sh.change_dir(&self.dir);
         let commit = commit.map(Ok).unwrap_or_else(|| {
@@ -38,7 +51,7 @@ impl GitSync {
         })?;
         // Make sure the repo is clean.
         if cmd!(sh, "git status --untracked-files=no --porcelain").read()?.is_empty().not() {
-            bail!("working directory must be clean before performing rustc pull");
+            return Err(anyhow::anyhow!("working directory must be clean before performing rustc pull").into());
         }
         // Make sure josh is running.
         let josh = Self::start_josh()?;
@@ -47,7 +60,7 @@ impl GitSync {
 
         let previous_base_commit = sh.read_file("rust-version")?.trim().to_string();
         if previous_base_commit == commit {
-            return Err(anyhow::anyhow!("No changes since last pull"));
+            return Err(RustcPullError::NothingToPull);
         }
 
         // Update rust-version file. As a separate commit, since making it part of
@@ -94,12 +107,13 @@ impl GitSync {
             cmd!(sh, "git reset --hard HEAD^")
                 .run()
                 .expect("FAILED to clean up after creating the preparation commit");
-            return Err(anyhow::anyhow!("No merge was performed, nothing to pull. Rolled back the preparation commit."));
+            eprintln!("No merge was performed, no changes to pull were found. Rolled back the preparation commit.");
+            return Err(RustcPullError::NothingToPull);
         }
 
         // Check that the number of roots did not increase.
         if num_roots()? != num_roots_before {
-            bail!("Josh created a new root commit. This is probably not the history you want.");
+            return Err(anyhow::anyhow!("Josh created a new root commit. This is probably not the history you want.").into());
         }
 
         drop(josh);